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St Johns Wort Tacrolimus Interaction — ESENeph MCQ

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EasyTransplantationSt Johns Wort Tacrolimus InteractionESENeph

A 65-year-old man with CKD G5D on haemodialysis wants to take an over-the-counter herbal supplement containing St John's Wort. He is also taking Tacrolimus (he has a failing kidney transplant). Why should this be avoided?

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Correct answer: B — St John's Wort is a CYP3A4 inducer that reduces Tacrolimus levels, risking rejection

St John's Wort (Hypericum perforatum) is a potent CYP3A4 and P-glycoprotein inducer. It significantly reduces blood levels of drugs metabolised by these pathways, including Tacrolimus, Ciclosporin, Warfarin, and DOACs. Reduced Tacrolimus levels risk acute rejection. BNF and MHRA contraindicate co-administration. Transplant recipients should be counselled about herbal supplements, many of which have significant drug interaction potential.

Reference: BNF 2024 – Tacrolimus Interactions; MHRA – St John's Wort Warning